U.S. patent application number 14/757943 was filed with the patent office on 2017-06-29 for process, apparatus and system for creating extrudable material having color effects and products made with extrudable material created with same.
This patent application is currently assigned to Pelican International, Inc.. The applicant listed for this patent is PELICAN INTERNATIONAL INC.. Invention is credited to Steve Jalbert, Mathieu Lemay.
Application Number | 20170182697 14/757943 |
Document ID | / |
Family ID | 59086881 |
Filed Date | 2017-06-29 |
United States Patent
Application |
20170182697 |
Kind Code |
A1 |
Lemay; Mathieu ; et
al. |
June 29, 2017 |
Process, apparatus and system for creating extrudable material
having color effects and products made with extrudable material
created with same
Abstract
A process and associated system for creating color effects in
extrudable material, such as plastic and metal for example, are
presented. Flows of first and second viscous materials of
respective colors are provided and then combined in a predetermined
pattern to form a stream of combined viscous material. In a first
aspect, the flow rate of the first viscous material is caused to
vary over time in order to vary an amount of the first viscous
material in the stream. In a second aspect, which may be used alone
or in combination with the first aspect, the first and second
viscous materials have distinct viscosities to reduce an amount of
color blending between the first color and the second color in the
stream of combined viscous material. A static mixer may then be
used to apply a predetermined dividing, overturning and combining
motion to the stream of combined viscous material to partially mix
the first viscous material and the second viscous material, such
that upon exiting the static mixer, the first material of the first
color and the second material of the second color form a color
pattern in the stream of combined viscous material. Sheets of
extrudable material may be created using such process and used in
the manufacturing of many different products including for example
kayaks and stand-up paddle boards.
Inventors: |
Lemay; Mathieu; (Mascouche,
CA) ; Jalbert; Steve; (Montreal, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PELICAN INTERNATIONAL INC. |
Laval |
|
CA |
|
|
Assignee: |
Pelican International, Inc.
|
Family ID: |
59086881 |
Appl. No.: |
14/757943 |
Filed: |
December 23, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 48/08 20190201;
B29B 7/603 20130101; B29C 48/022 20190201; B29C 48/362 20190201;
B29C 2948/926 20190201; B63B 32/20 20200201; B29C 48/92 20190201;
B29B 7/7466 20130101; B29C 2948/92952 20190201; B29C 51/14
20130101; B29K 2995/0021 20130101; B29C 48/09 20190201; B29B 7/728
20130101; B29C 48/06 20190201; B29C 48/07 20190201; B29C 48/495
20190201; B29C 48/0017 20190201; B29C 48/21 20190201; B29K 2995/002
20130101; B29C 2948/9259 20190201; B29B 7/88 20130101; B29L 2031/52
20130101; B29C 2948/92752 20190201; B63B 32/00 20200201; B29C 48/17
20190201; B29C 48/175 20190201; B29C 2948/92904 20190201; B29C
2948/92885 20190201; B63B 34/20 20200201; B29B 7/325 20130101; B29L
2031/5272 20130101; B29C 51/02 20130101 |
International
Class: |
B29C 47/04 20060101
B29C047/04; B29B 7/74 20060101 B29B007/74; B29C 51/14 20060101
B29C051/14; B29C 47/92 20060101 B29C047/92; B29B 7/32 20060101
B29B007/32; B29C 47/00 20060101 B29C047/00 |
Claims
1) A process for creating color effects in extrudable material,
said process comprising: a) providing a flow of a first viscous
material of a first color, wherein the flow of the first viscous
material is associated with a first rate of flow and wherein
providing the flow of the first viscous material of the first color
includes varying the first rate of flow over time; b) providing a
flow of a second viscous material of a second color different from
the first color, wherein the flow of the second viscous material is
associated with a second rate of flow; c) combining in a
predetermined pattern the flow of the first viscous material and
the flow of the second viscous material to form a stream of
combined viscous material.
2) A process as defined in claim 1, wherein varying the first rate
of flow over time includes causing the first rate of flow to
oscillate between a lower flow rate threshold and an upper flow
rate threshold over a time interval.
3) A process as defined in claim 2, wherein said process comprising
setting at least one of the lower flow rate threshold, the time
interval and the upper flow rate threshold in order to control at
least in part visual characteristics of the color pattern in the
stream of combined viscous material.
4) A process as defined in claim 3, wherein setting at least one of
the lower flow rate threshold, the time interval and the upper flow
rate threshold includes entering control commands on a computer
operated control circuit.
5) (canceled)
6) (canceled)
7) A process as defined in claim 1, wherein the second rate of flow
associated with the flow of the second viscous material is kept
substantially constant over time.
8) A process as defined in claim 1, wherein the second rate of flow
is lower than the first rate of flow.
9) (canceled)
10) (canceled)
11) (canceled)
12) A process as defined in claim 1, wherein said first viscous
material has a first viscosity and said second viscous material has
a second viscosity, said first viscosity being distinct from said
second viscosity.
13) (canceled)
14) A process as defined in claim 12, wherein said first viscous
material is associated with a first high load melt index (first
HLMI) and wherein said second viscous material is associated with a
second high load melt index (second HLMI), said first HLMI being
greater than said second HLMI.
15) A process as defined in claim 13, wherein said first HLMI is at
least about ten times (10.times.) said second HLMI.
16) (canceled)
17) (canceled)
18) A process as defined in claim 1, wherein said first viscous
material and said second viscous material are viscous plastic
materials.
19) A process as defined in claim 18, wherein the first color of
the first viscous material is a translucide color.
20) A process as defined in claim 1, said process comprising using
a static mixer to apply a predetermined dividing, overturning and
combining motion to said stream of combined viscous material to
partially mix the first viscous material and the second viscous
material, such that upon exiting the static mixer, the first
material of the first color and the second material of the second
color form a color pattern in the stream of combined viscous
material.
21) (canceled)
22) A process as defined in claim 20, wherein after applying the
dividing, overturning and combining motion, said process includes
the step of forming said stream of combined viscous material into
one of a sheet or a tube.
23) (canceled)
24) A process as defined in claim 20, wherein after applying the
dividing, overturning and combining motion, feeding the stream of
combined viscous material through a die for forming a sheet of
material comprising a wave-live color pattern.
25) A process for creating color effects in extrudable material,
said process comprising: a) providing a flow of a first viscous
material of a first color; b) providing a flow of a second viscous
material of a second color different from the first color; c)
combining in a predetermined pattern the flow of the first viscous
material and the flow of the second viscous material to form a
stream of combined viscous material; d) using a static mixer
applying a predetermined dividing, overturning and combining motion
to said stream of combined viscous material to partially mix the
first viscous material and the second viscous material, such that
such that upon exiting the static mixer, the first material of the
first color and the second material of the second color form a
color pattern in the stream of combined viscous material, wherein:
i) the flow of the first viscous material is associated with a
first viscosity; and ii) the flow of the second viscous material is
associated with a second viscosity, said first viscosity being
distinct from said second viscosity to reduce an amount of color
blending between the first color and the second color in the stream
of combined viscous material when the static mixer applies the
predetermined dividing, overturning and combining motion to said
stream of combined viscous material.
26) A process as defined in claim 25, wherein said first viscosity
is lower than said second viscosity.
27) A process as defined in claim 25, wherein said first viscous
material is associated with a first high load melt index (first
HLMI) and wherein said second viscous material is associated with a
second high load melt index (second HLMI), said first HLMI being
greater than said second HLMI.
28) A process as defined in claim 27, wherein said first HLMI is at
least about ten times (10.times.) said second HLMI.
29) (canceled)
30) A process as defined in claim 27, wherein said first HLMI is at
least about one hundred times (100.times.) said second HLMI.
31) A process as defined in claim 25, wherein said first viscous
material and said second viscous material are viscous plastic
materials.
32) A process as defined in claim 31, wherein the first color of
the first viscous material is a translucide color.
33) (canceled)
34) (canceled)
35) (canceled)
36) (canceled)
37) A process as defined in claim 25, wherein after applying the
dividing, overturning and combining motion, said process includes
the step of forming said stream of combined viscous material into
one of a sheet and a tube.
38) (canceled)
39) A process as defined in claim 25, wherein after applying the
dividing, overturning and combining motion, feeding the stream of
combined viscous material through a die for forming a sheet of
material.
40) A system for creating color effects in extrudable material,
said system comprising: a) a first extruder for providing a flow of
a first viscous material of a first color, the first extruder
providing the flow of the first viscous material at a first rate of
flow, the first extruder being operatively connected to a flow rate
controller configured for varying the first rate of flow over time;
b) a second extruder for providing a flow of a second viscous
material of a second color different from the first color, the
second extruder providing the flow of the second viscous material
at a second rate of flow; c) a feed block for combining the flow of
the first viscous material and the flow of the second viscous
material to form a stream of combined viscous material.
41) A system as defined in claim 40, wherein the flow rate
controller includes an electronic control element configured for
causing the first rate of flow to vary over time at least in part
by causing a variable speed motor to vary a speed of operation of
an extruder screw in the first extruder.
42) A system as defined in claim 40, wherein the flow rate
controller includes a variable speed motor configured for operating
an extruder screw in the first extruder and an electronic control
element configured for controlling the variable speed motor to
cause the first rate of flow to vary over time at least in part by
causing the variable speed motor to vary the speed of operation of
the extruder screw.
43) A system as defined in claim 40, wherein the flow rate
controller is configured for varying the first rate of flow over
time at least in part by causing the first rate of flow to
oscillate between a lower flow rate threshold and an upper flow
rate threshold over a time interval.
44) A system as defined in claim 43, wherein the flow rate
controller provides one or more user operable controls for allowing
a user to set at least one of the lower flow rate threshold, the
time interval and the upper flow rate threshold in order to control
at least in part visual characteristics of the color pattern in the
stream of combined viscous material.
45) (canceled)
46) A system as defined in claim 40, wherein the second rate of
flow associated with the flow of the second viscous material is
kept substantially constant over time.
47) A system as defined in claim 40, wherein the second rate of
flow is lower than the first rate of flow.
48) A system as defined in claim 47, wherein the second rate of
flow is no more than 50% of the first rate of flow.
49) (canceled)
50) (canceled)
51) (canceled)
52) (canceled)
53) (canceled)
54) A system as defined in claim 40, further comprising a static
mixer for receiving the stream of combined viscous material from
the feed block, wherein the static mixer is configured to apply a
predetermined dividing, overturning and combining motion to said
stream of combined viscous material to partially mix the first
viscous material and the second viscous material such that, upon
exiting the static mixer, the first material of the first color and
the second material of the second color form a color pattern in the
stream of combined viscous material.
55) (canceled)
56) The system as defined in claim 54, further comprising a die for
receiving the stream of combined viscous material from said static
mixer, said die being configured for forming said stream of
combined viscous material into either one of a sheet or a tube.
57) (canceled)
58) The system as defined in claim 54, further comprising: a) at
least one additional extruder for providing at least one additional
flow of a third viscous material; b) a combining device for
combining the stream of combined viscous material released by the
static mixer with the at least one additional stream of third
viscous material provided by the at least one additional
extruder.
59) A system as defined in claim 58, wherein said combining device
forms a co-extruded stream having at least two layers.
60) The system as defined in claim 40, wherein said first viscous
material is a first viscous plastic and said second viscous
material is a second viscous plastic.
61) A system for creating color effects in extrudable material,
said system comprising: a) a first extruder for providing a flow of
a first viscous material of a first color; b) a second extruder for
providing a flow of a second viscous material of a second color
different from the first color; c) a feed block for combining the
flow of the first viscous material and the flow of the second
viscous material to form a stream of combined viscous material; d)
a static mixer for receiving the stream of combined viscous
material from the feed block, wherein the static mixer is
configured to apply a predetermined dividing, overturning and
combining motion to said stream of combined viscous material to
partially mix the first viscous material and the second viscous
material such that, upon exiting the static mixer, the first
material of the first color and the second material of the second
color form a color pattern in the stream of combined viscous
material, wherein: i) the flow of the first viscous material is
associated with a first viscosity; and ii) the flow of the second
viscous material is associated with a second viscosity, said first
viscosity being distinct from said second viscosity to reduce an
amount of color blending between the first color and the second
color in the stream of combined viscous material when the static
mixer applies the predetermined dividing, overturning and combining
motion to said stream of combined viscous material.
62) A process for manufacturing a plastic article comprising color
effects, said process comprising: a) manufacturing sheets of
extrudable plastic material having color effects using a process
defined in claim 1; b) molding one or more of the manufactured
sheets of extrudable material using thermoforming to shape the one
or more manufactured sheets into the plastic article.
63) A process as defined in claim 62, wherein the plastic article
is one of a sled and a stand-up paddle board.
64) A process for manufacturing a kayak comprising color effects,
said process comprising molding two or more manufactured sheets of
extrudable material using thermoforming to shape the two of more
manufactured sheets into a kayak shape, at least one of the two or
more of the manufactured sheets having color effects created using
a process defined in claim 1.
65) A plastic article manufactured at least in part using a sheet
of extrudable material having color effects created at least in
part by a process defined in claim 1.
66) A kayak manufactured at least in part using a sheet of
extrudable material having color effects created at least in part
by a process defined in claim 1.
67) (canceled)
68) A sheet of extrudable material having color effects, said sheet
of extrudable material being comprised of: a) a first viscous
material of a first color; b) a second viscous material of a second
color different from the first color, wherein the first viscous
material has a first viscosity and the second viscous material has
a second viscosity, the first viscosity being distinct from the
second viscosity to reduce an amount of color blending between the
first color and the second color in the sheet.
69) (canceled)
70) (canceled)
71) (canceled)
72) (canceled)
73) (canceled)
74) (canceled)
75) (canceled)
76) (canceled)
77) (canceled)
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to the field of
extrusion processes and extrudable materials created using such
processes, including for example plastic or metal materials. More
specifically, the present invention relates to processes and
associated apparatuses and systems for creating extrudable
materials having color effects as well as to products made with
extrudable materials having color effects created using such
processes.
BACKGROUND
[0002] Extrusion processes are commonly used in a variety of
different industries, and with a multitude of different types and
grades of material, for forming and shaping these materials into
articles.
[0003] Extruded products, whether plastic, metal or some other
material, are often uniform in color. In some cases, the extruded
products are formed of several layers of material, including one or
more visible, outer layers and one or more hidden, inner layers,
where these layers may differ in color.
[0004] In today's competitive market place, it is important for
companies to have an edge that distinguishes their product from a
competitor's product. One way to create a product that
distinguishes itself from a competitor's product is to provide the
product with an aesthetically pleasing and/or original appearance.
Consumers are typically attracted to products having a visually
appealing look.
[0005] In the field of extruded products, one method for giving the
end products a visually appealing look is to create special color
effects in the material of the product. Existing methods for
producing color effects in extruded material, such as plastic for
example, include lamination techniques, wherein multiple different
layers of colored material are joined together to form a
multi-colored sheet, and imprinting techniques wherein an imprinted
film is adhered to the material. Unfortunately, these processes
require treating the material after it has been extruded and
formed. This can be both costly and time consuming.
[0006] Other methods, such as the one described for example in U.S.
Pat. No. 7,204,944, allow producing color effects in the form of
color bands in the extruded material by combining flows of viscous
material of multiple colors during the extrusion process to form a
stream of viscous material characterized by bands of different
colors. The contents of the aforementioned document are
incorporated herein by reference. While approaches of the type
described above may allow creating extruded material having a
pleasing and original visual appearance, the visual effects that
may be produced tend to be limited. In order to attract the
attention of consumers, it is desirable to create a variety of
original color effects in extruded materials include some that may
differ from those that may be created by methods of the type
proposed in U.S. Pat. No. 7,204,944.
[0007] As such, a need exists in the industry to provide methods
for producing visually appealing color effects in extrudable
material, such as plastic and metal.
SUMMARY
[0008] In accordance with a first aspect, a process for creating
color effects in extrudable material is described. The process
comprises providing a flow of a first viscous material of a first
color, wherein the flow of the first viscous material is associated
with a first rate of flow and wherein providing the flow of the
first viscous material of the first color includes varying the
first rate of flow over time. The process also comprises providing
a flow of a second viscous material of a second color different
from the first color, wherein the flow of the second viscous
material is associated with a second rate of flow. The process also
comprises combining in a predetermined pattern the flow of the
first viscous material and the flow of the second viscous material
to form a stream of combined viscous material.
[0009] Varying the rate of flow of the first viscous material over
time may allow modulating over time an amount of the first viscous
material, relative to an amount of the second viscous material,
that finds itself in the stream of combined viscous material at
different moments in time, which may allow the color effects
created to vary over time and may allow creating wave-like color
gradation effects.
[0010] In some specific practical implementations, varying the
first rate of flow over time may include causing the first rate of
flow to oscillate between a lower flow rate threshold and an upper
flow rate threshold over a time interval. The time interval may
have any suitable duration. In specific non-limiting
implementations, the duration has ranged between at least about 20
seconds and about 1 minute however any suitable duration for the
time interval may be contemplated including shorter and intervals
or more lengthy intervals. Optionally, in some embodiments, the
process may include setting the lower flow rate threshold and/or
the upper flow rate threshold and/or the time interval in order to
control at least in part visual characteristics of the color
pattern in the stream of combined viscous material. In specific
practical implementations, any suitable mechanism may be provided
to enable a user to provide control command for setting or
modifying the lower flow rate threshold and/or the upper flow rate
threshold and/or the time interval. Such suitable mechanism may
include, without being limited to, providing user operable controls
in communication with an electronic control element.
[0011] In some specific practical implementations, the second rate
of flow associated with the flow of the second viscous material may
be kept substantially constant over time. Alternatively, the second
rate of flow may also be caused to vary over a time period so that
the flows of both the first viscous material and the second viscous
material are caused to vary over time. In such alternative
implementations, the time intervals over which the first viscous
material and the second viscous material vary need not be the
same.
[0012] In some specific practical implementations, the second rate
of flow associated with the second viscous material of the second
color may be lower than the first rate of flow. In such
implementations, the first viscous material constitutes a larger
portion of the resulting stream of combined viscous material than
the second viscous material. In specific practical implementations,
the second rate of flow may be no more than 50% of the first rate
of flow, preferably no more than 30% of the first rate of flow and
more preferably no more than 20% of the first rate of flow.
[0013] In some specific practical implementations, the first
viscous material has a first viscosity and the second viscous
material has a second viscosity, wherein first viscosity may be
distinct from the second viscosity to reduce an amount of color
blending between the first color and the second color in the stream
of combined viscous material.
[0014] In some specific practical implementations, the first
viscous material is associated with a first high load melt index
(first HLMI) and the second viscous material is associated with a
second high load melt index (second HLMI), where the first HLMI may
be greater than the second HLMI. The difference between the high
load melt indices of the first and second viscous mates may be
selected in such a way as to control the amount of blending that
may occur between the different colors of the first and second
viscous materials. In specific practical implementations, the first
HLMI may be at least about ten times (10.times.) the second HLMI;
the first HLMI may also be at least about twenty times (20.times.)
the second HLMI; the first HLMI may also be at least about one
hundred times (100.times.) the second HLMI. Typically, the greater
the difference between the HLMIs the lesser the extent of the color
blending in the stream of combined viscous material.
[0015] In some specific practical implementations, the first
viscous material and the second viscous material may be viscous
plastic materials, metal materials or some other viscous
materials.
[0016] In some specific practical implementation, the first color
of the first viscous material may be a translucent color.
[0017] In some specific implementations, the process may also
comprises using a static mixer to apply a predetermined dividing,
overturning and combining motion to the stream of combined viscous
material to partially mix the first viscous material and the second
viscous material, such that upon exiting the static mixer, the
first material of the first color and the second material of the
second color form a color pattern in the stream of combined viscous
material. In a specific practical implementation, the static mixer
may include a helical mixer.
[0018] In some specific implementations, after applying the
dividing, overturning and combining motion, the process may include
the step of forming the stream of combined viscous material into a
sheet or, alternatively, forming the stream of combined viscous
material into a tube.
[0019] In some specific implementations, after applying the
dividing, overturning and combining motion, the process may include
feeding the stream of combined viscous material through a die for
forming a sheet of material comprising a wave-like color gradation
effect.
[0020] In accordance with a second aspect, a process for creating
color effects in extrudable material is described comprising
providing a flow of a first viscous material of a first color and
providing a flow of a second viscous material of a second color
different from the first color. The process also comprises
combining in a predetermined pattern the flow of the first viscous
material and the flow of the second viscous material to form a
stream of combined viscous material. The process also comprises
using a static mixer to apply a predetermined dividing, overturning
and combining motion to the stream of combined viscous material to
partially mix the first viscous material and the second viscous
material, such that the first material of the first color and the
second material of the second color form a color pattern in the
stream of combined viscous material, wherein: [0021] i) the flow of
the first viscous material is associated with a first viscosity;
and [0022] ii) the flow of the second viscous material is
associated with a second viscosity, the first viscosity being
distinct from the second viscosity to reduce an amount of color
blending between the first color and the second color in the stream
of combined viscous material when the static mixer applies the
predetermined dividing, overturning and combining motion to the
stream of combined viscous material.
[0023] In some specific practical implementations, the first
viscous material is associated with a first high load melt index
(first HLMI) and the second viscous material is associated with a
second high load melt index (second HLMI), where the first HLMI may
be greater than the second HLMI. The difference between the high
load melt indices of the first and second viscous mates may be
selected in such a way as to control the amount of blending that
may occur between the different colors of the first and second
viscous materials. In specific practical implementations, the first
HLMI may be at least about ten times (10.times.) the second HLMI;
the first HLMI may also be at least about twenty times (20.times.)
the second HLMI; the first HLMI may also be at least about one
hundred times (100.times.) the second HLMI. Typically, the greater
the difference between the HLMIs the lesser the extent of the color
blending in the stream of combined viscous material.
[0024] In a specific, non-limiting example of implementation,
processes of the type described above may be implemented in a
system for manufacturing plastic sheets. The system may include' a
die, a feed block and at least two extruders. The extruders may
each be configured to mix and heat plastic granules, for producing
a generally homogeneous, viscous plastic mixture. In the context of
the present invention, at least two of the extruders produce
plastic mixtures of different colors and of different viscosities.
The feed block is configured to combine the flows of viscous
plastic released by the different extruders into a single stream of
combined viscous material. The single stream of viscous plastic
generated by the feed block may be fed through a static mixer pipe.
The static mixer pipe is configured to act on the single stream of
combined viscous material to partially mix the stream and create a
color pattern in the stream of combined viscous material. The die
receives the partially mixed stream of combined viscous material
from the static mixer pipe, and may be configured to shape the
stream into its final product form, such as a sheet or a tube,
among many other possibilities.
[0025] In accordance with a third aspect, a system for creating
color effects in extrudable material is provided, the system
comprising a first extruder for providing a flow of a first viscous
material of a first color, the first extruder providing the flow of
the first viscous material at a first rate of flow, the first
extruder being in communication with a flow rate controller
configured for varying the first rate of flow over time. The system
further comprises a second extruder for providing a flow of a
second viscous material of a second color different from the first
color, the second extruder providing the flow of the second viscous
material at a second rate of flow. The system further comprises a
feed block for combining the flow of the first viscous material and
the flow of the second viscous material to form a stream of
combined viscous material.
[0026] In some specific practical implementations, the flow rate
controller associated with the first extruder may include an
electronic control element configured for causing the first rate of
flow to vary over time at least in part by causing a variation in a
speed of operation of an extruder screw in the first extruder. More
specifically, the flow rate controller may include a variable speed
motor configured for operating the extruder screw of the first
extruder and an electronic control element programmed for
controlling the variable speed motor. The electronic control
element may be programmed to cause the first rate of flow to vary
over time at least in part by causing the variable speed motor to
vary the speed of operation of the extruder screw.
[0027] In a specific practical implementation, the flow rate
controller may be configured for varying the first rate of flow
over time at least in part by causing the first rate of flow to
oscillate between a lower flow rate threshold and an upper flow
rate threshold over a time interval. Optionally, in some
embodiments, the flow rate controller may provide one or more user
operable controls for allowing a user to set the lower flow rate
threshold and/or the upper flow rate threshold and/or the time
interval in order to control at least in part visual
characteristics of the color pattern in the stream of combined
viscous material exiting the system.
[0028] In some specific practical implementations, the second rate
of flow associated with the flow of the second viscous material may
be kept substantially constant over time. Alternatively, the second
rate of flow may also be caused to vary over a time period so that
the flows of both the first viscous material and the second viscous
material are caused to vary over time. In such alternative
implementations, the time intervals over which the first viscous
material and the second viscous material vary need not be the
same.
[0029] In some specific practical implementations, the second rate
of flow associated with the second viscous material of the second
color may be lower than the first rate of flow. In such
implementations, the first viscous material constitutes a larger
portion of the resulting stream of combined viscous material than
the second viscous material. In specific practical implementations,
the second rate of flow may be no more than 50% of the first rate
of flow, preferably no more than 30% of the first rate of flow and
more preferably no more than 20% of the first rate of flow.
[0030] In some specific practical implementations, the system may
further comprise a static mixer for receiving the stream of
combined viscous material from the feed block. The static mixer is
configured to apply a predetermined dividing, overturning and
combining motion to the stream of combined viscous material to
partially mix the first viscous material and the second viscous
material such that, upon exiting the static mixer, the first
material of the first color and the second material of the second
color form a color pattern in the stream of combined viscous
material.
[0031] In some specific practical implementations, the system may
further comprise a die for receiving the stream of combined viscous
material from the static mixer, the die being configured for
forming the stream of combined viscous material into a sheet or
into a tube.
[0032] In some specific practical implementations, the system may
further comprise at least one additional extruder for providing at
least one additional flow of a third viscous material and a
combining device for combining the stream of combined viscous
material released by the static mixer with the at least one
additional stream of the third viscous material provided by the at
least one additional extruder. The combining device may be
configured for forming a co-extruded stream having at least two
layers using the stream of the third viscous material and the
stream of combined viscous material.
[0033] In accordance with a fourth aspect, a system for creating
color effects in extrudable material is provided. The system
comprises a first extruder for providing a flow of a first viscous
material of a first color and a second extruder for providing a
second viscous material of a second color different from the first
color. The system further comprises a feed block for combining the
flow of the first viscous material and the flow of the second
viscous material to form a stream of combined viscous material. The
system further comprises a static mixer for receiving the stream of
combined viscous material from the feed block, wherein the static
mixer is configured to apply a predetermined dividing, overturning
and combining motion to said stream of combined viscous material to
partially mix the first viscous material and the second viscous
material such that, upon exiting the static mixer, the first
material of the first color and the second material of the second
color form a color pattern in the stream of combined viscous
material. The flow of the first viscous material is associated with
a first viscosity and the flow of the second viscous material is
associated with a second viscosity, the first viscosity being
distinct from the second viscosity to reduce an amount of color
blending between the first color and the second color in the stream
of combined viscous material when the static mixer applies the
predetermined dividing, overturning and combining motion to the
stream of combined viscous material.
[0034] In accordance with another aspect, a process for
manufacturing a plastic article comprising color effects is
presented. The process comprises molding two or more of the
manufactured sheets of extrudable material using thermoforming to
shape the two of more manufactured sheets into a kayak shape, at
least one of the two or more of the manufactured sheets having
color effects created using a process of the type described
above.
[0035] In specific practical implementations, an other one of the
two or more of the manufactured sheets may have a uniform color or,
alternatively, may also have color effects created using a process
of the type described above.
[0036] In specific practical implementations, the process may be
suitable for use during manufacturing of many different types of
products including, but without being limited to, kayaks, sleds and
stand-up paddle boards amongst many others.
[0037] In accordance with another aspect, a sheet of extrudable
material having color effects is presented, the sheet of extrudable
material being comprised of a first viscous material of a first
color and a second viscous material of a second color different
from the first color, wherein the first viscous material has a
first viscosity and the second viscous material has a second
viscosity, the first viscosity being distinct from the second
viscosity to reduce an amount of color blending between the first
color and the second color in the sheet.
[0038] In some specific practical implementations, the first
viscous material of the sheet is associated with a first high load
melt index (first HLMI) and the second viscous material is
associated with a second high load melt index (second HLMI), where
the first HLMI may be greater than the second HLMI. The difference
between the high load melt indices of the first and second viscous
mates may be selected in such a way as to control the amount of
blending that may occur between the different colors of the first
and second viscous materials. In specific practical
implementations, the first HLMI may be at least about ten times
(10.times.) the second HLMI; the first HLMI may also be at least
about twenty times (20.times.) the second HLMI; the first HLMI may
also be at least about one hundred times (100.times.) the second
HLMI.
[0039] In accordance with another aspect, a process for creating
color effects in extrudable material is described in which the
process comprises: [0040] a) providing a flow of a first viscous
material of a first color; [0041] b) providing a flow of a second
viscous material of a second color different from the first color;
[0042] c) combining in a predetermined pattern the flow of the
first viscous material and the flow of the second viscous material
to form a stream of combined viscous material; [0043] d) using a
static mixer applying a predetermined dividing, overturning and
combining motion to said stream of combined viscous material to
partially mix the first viscous material and the second viscous
material, such that such that upon exiting the static mixer, the
first material of the first color and the second material of the
second color form a color pattern in the stream of combined viscous
material, wherein the color pattern in the stream is configured at
least in part based on a radial orientation of the static
mixer.
[0044] In some specific practical implementations, the process may
comprise altering the color pattern in the stream by performing a
rotation of the static mixer by a pre-determined rotation amount to
change the radial orientation of the static mixer. In specific
practical implementation, the pre-determined rotation amount may be
established based on an internal structure of the static mixer such
that upon exiting the static mixer a desired effect may be achieved
in the stream of viscous material. In specific practical
implementations, the pre-determined rotation amount may be a
rotation of about 45.degree., 90.degree., 135.degree. or
180.degree..
[0045] All features of embodiments which are described in this
disclosure and are not mutually exclusive can be combined with one
another. Elements of one embodiment can be utilized in the other
embodiments without further mention.
[0046] Other aspects and features of the present invention will
become apparent to those ordinarily skilled in the art upon review
of the following description of specific embodiments of the
invention in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] A detailed description of specific embodiments of the
present invention is provided herein below with reference to the
accompanying drawings in which:
[0048] FIG. 1 illustrates a system for manufacturing plastic
sheets, according to a non-limiting example of implementation of
the present invention;
[0049] FIG. 2 depicts components of a flow rate controller that may
be used in connection with an extruder of the system of FIG. 1;
[0050] FIG. 3 depicts an electronic control element of the flow
rate controller of FIG. 2 in accordance with a non-limiting
embodiment of the present invention;
[0051] FIGS. 4A and 4B are charts illustrating variations in a
speed of operation of an extruder screw in order to cause variation
in a flow rate in connection with an extruder of the system of FIG.
1;
[0052] FIG. 5A shows color effects that may be produced in
extrudable plastic material using a system of the type shown in
FIG. 1 in which the flow rate controller maintains a constant flow
rate;
[0053] FIG. 5B shows color effects that may be produced in
extrudable plastic material using a system of the type shown in
FIG. 1 in which the flow rate controller varies the flow rate over
time of the material released by an extruder;
[0054] FIG. 6 depicts an example of a possible structural
configuration for a feed block shown in FIG. 1;
[0055] FIG. 7 is a perspective view of a helical static mixer;
[0056] FIG. 8 is a perspective view of a different type of static
mixer;
[0057] FIG. 9A shows examples cross-sectional views of combined
streams of viscous material entering the static mixer 108 of the
system 100 shown in FIG. 1 in accordance with non-limiting examples
of implementation, the examples including (a) a first viscous
material ("A") only; (b) first viscous material ("A") and second
viscous material ("D"); and (c) first viscous material ("A"),
second viscous material ("D") and third viscous material ("E");
[0058] FIGS. 9B, 9C and 9D shows other examples of cross-sectional
views of combined streams of viscous material entering the static
mixer 108 of the system 100 shown in FIG. 1 in accordance with
non-limiting examples of implementation;
[0059] FIG. 10 illustrates a combined stream of viscous material as
it exits the static mixer in accordance with a non-limiting
implementation;
[0060] FIG. 11A depicts a sheet of plastic with wave-like color
gradation effects created in accordance with a non-liming example
of implementation of the invention;
[0061] FIG. 11B depicts a tube of plastic with wave-like color
gradation effects in accordance with another non-liming example of
implementation of the invention;
[0062] FIG. 12 is a flowchart illustrating a process for creating
color effects in extruded material according to an example of
implementation of the present invention; and
[0063] FIG. 13 depicts a system for manufacturing plastic sheets
according to a variant of implementation of the present
invention;
[0064] FIG. 14A shows kayaks manufactured using plastic sheets of
extrudable material created using a process embodying aspects of
the invention;
[0065] FIGS. 14B and 14C show top plan and side views respectively
of a stand-up paddle board (SUP) manufactured using plastic sheets
of extrudable material created using a process embodying aspects of
the invention.
[0066] In the drawings, embodiments of the invention are
illustrated by way of examples. It is to be expressly understood
that the description and drawings are only for the purpose of
illustration and are an aid for understanding. They are not
intended to be a definition of the limits of the invention.
DETAILED DESCRIPTION
[0067] The present invention is directed to a process and apparatus
for creating color effects in extruded material, such as plastic or
metal.
[0068] In the following examples of implementation, the present
invention will be described for use in creating color effects in
extruded plastic material. However, it is to be appreciated that
the invention is not limited to any particular type of material.
Rather, the concepts described in the present document may be
applied to different types and grades of extrudable material.
[0069] FIG. 1 depicts a system 100 for manufacturing plastic
sheets, according to a non-limiting example of implementation of
the present invention. The system 100 shown is formed of several
components, including a die 102, a feed block 104, a first
(primary) extruder 106 for providing a first material ("A") and one
or more secondary extruders 120.sub.1, . . . ,120.sub.N, where the
number N of secondary extruders 120.sub.1, . . . ,120.sub.N in the
system 100 is at least one.
[0070] Note that, in alternative embodiments, the system 100 may
include two or more secondary extruders 120.sub.1, . . .
,120.sub.N.
[0071] Extruder 106 and each extruder 120.sub.1, . . . 120.sub.N is
operative to mix and heat plastic granules. The granules are heated
to a predetermined temperature, sufficient to cause melting of the
granules for producing a homogeneous, viscous plastic mixture.
[0072] Examples of the different types of thermoplastics that can
be extruded include: LDPE, HDPE, ABS, polystyrene, polypropylene,
acetates, butyrates, nylons, polyphenylene sulfides, acetals,
polycarbonates and thermoplastic rubbers and polyesters, among
other possibilities.
[0073] Typically, a controlled amount of colorant is added to the
mixture in extruder 106 and in each extruder 120.sub.1, . . .
,120.sub.N, for obtaining viscous plastic mixtures of respective
specific colors. Different techniques, known in the art, may be
used to color the plastic mixtures in the extruders 106 and
120.sub.1, . . . ,120.sub.N. In one example, colorant in the form
of granules is added to and mixed with the plastic granules before
they are fed into the extruders 106 and 120.sub.1, . . . ,120.sub.N
for melting. In another example, colorant in liquid form may be fed
into the extruders for mixing with the plastic granules.
Alternatively, the non-recycled plastic granules themselves can be
pre-colored such that it is not necessary to add colorant to the
mixture. In another alternative, recycled plastic granules of a
specific color may be used in the extruders 106 120.sub.1, . . .
,120.sub.N, such that the addition of a colorant is not
required.
[0074] In a specific practical implementation, the mixture "A" used
in the primary extruder 106 may be a translucent material and the
mixture "D" in the secondary extruders 120.sub.1 may be a mixture
of a specific color. Similarly, the mixture "E" in another
secondary extruder 120.sub.N may be a mixture of a specific color,
which may be the same or distinct from the color of mixture "D"
used in the secondary extruder 120.sub.1.
[0075] The primary extruder 106 is configured to melt and mix the
plastic granules such that the mixture 110, which is released from
extruder 106, is perfectly melted and homogeneous, both in
temperature and in color, upon its exit from the extruder 106.
[0076] Similarly, a secondary extruder 120 is configured to melt
and mix the plastic granules such that the mixture 122, which is
released from a secondary extruder 120, is also perfectly melted
and homogeneous, both in temperature and in color, upon exit from
the extruder 120.
[0077] Note that, with regard to the plastic mixture released by
the primary extruder 106, the term "melted" implies that the
mixture is characterized by a viscous or semi-fluid flow. The
plastic mixture 110 released is also referred to herein as a flow
of a first viscous material 110. The extruder 106 releases the flow
of the first viscous material at a first rate of flow. The first
rate of flow may be any suitable rate flow depending on the type of
extrudable material that is being created by the system 100, for
example 400 kg/hr, 300 kg/hr, 100 kg/hr or 50 kg/hr, among many
other possibilities. As will be described in greater detail later
on in the present document, the flow of the first viscous material
110 may be provided at a first rate of flow that can be caused to
vary over time.
[0078] With regard to the plastic mixture output by the secondary
extruders 120.sub.1, . . . ,120.sub.N, the term "melted" also
implies that the mixture is characterized by a viscous or
semi-fluid flow. The plastic mixture 122 output by each extruder
120 is also referred to herein as a flow of a (second) viscous
material 122. Each one of the secondary extruders 120 may be set to
a respective rate of flow, for example 400 kg/hr, 300 kg/hr, 100
kg/hr, 50 kg/hr, 25 kg/hr or 10 kg/hr among many other
possibilities. In the embodiment shown in FIG. 1, during the
creation of an extruded material, the secondary extruders
120.sub.1, . . . ,120.sub.N may be set to operate such as to
release the plastic mixtures 122 at respective rates of flow that
are kept substantially constant over time. It is however to be
appreciated that, in alternate embodiments, the rates of flow of
material released by any of the secondary extruders 120.sub.1, . .
. ,120.sub.N may be caused to vary over a time period so that flows
of both the viscous material released by the primary extruder 106
and one or more of the secondary extruders 120.sub.1, . . .
,120.sub.N are caused to vary over time. It is also to be
appreciated that, in such alternative embodiments, the time
intervals over which the viscous material released by the primary
extruder 106 and the viscous material released by or more of the
secondary extruders 120.sub.1, . . . ,120.sub.N are caused to vary
need not be the same.
[0079] The structure and functionality of extruders are well known
to those skilled in the art, and will not be described in further
detail.
[0080] In the embodiment depicted in FIG. 1, the primary extruder
106 is in communication with a flow rate controller 152 configured
for varying over time the rate of flow of the viscous material 110
released by the primary extruder 106.
[0081] As depicted in FIG. 2, the flow rate controller 152
associated with the primary extruder 106 may include an electronic
control element 606 configured for causing the first rate of flow
of the viscous material 110 to vary over time. More specifically,
and as shown in the specific embodiment depicted, the flow rate
controller 152 may include a variable speed motor 604 configured
for operating at different speeds an extruder screw 602 in the
extruder 106. In this embodiment, the electronic control element
606 includes a processor (not shown) programmed for releasing
control signals for controlling the speed of operation of the
variable speed motor 604, which in turn causes a variation in a
speed of rotation of the extruder screw 602 in the primary extruder
106. Any suitable manner for controlling the speed of operation of
the variable speed motor 604 may be used and such manners are known
in the art and will not be described further here.
[0082] In a specific practical implementation, the flow rate
controller 152 may be configured for varying the first rate of flow
over time at least in part by causing the first rate of flow to
oscillate between a lower flow rate threshold and an upper flow
rate threshold over a certain time interval.
[0083] In specific practical implementation, the lower flow rate
threshold, the upper flow rate threshold and/or the time period may
be preset, for example by a programmed element stored in the flow
rate controller 152. Optionally, the lower flow rate threshold
and/or the upper flow rate threshold and/or the time period may be
set (or modified) by an operator of the system 100 in order to
control at least in part visual characteristics of the color
pattern in the stream of combined viscous material that will be
generated by the system 100. For example by shortening the time
period, more compact visual wave-like effects may be caused in the
resulting output stream of combined viscous material while
extending the time period may allow smoother/software visual
wave-like effects to be created. The time period may be set to any
suitable duration in dependence on the desired visual effect to be
created in the extrudable material. In non-limiting practical
implementations, the time interval used tends to range between
about 20 seconds and about 1 minute. If we look now to the flow
rate thresholds, increasing the upper flow rate threshold would
tend to cause an increased volume of the first viscous material
("A") to be pushed towards the feed block 104, which in turn causes
a greater amount of this substance to find itself in the resulting
output stream of combined viscous material. Analogously, decreasing
the lower flow rate threshold would tend to cause a reduced volume
of the first viscous material ("A") to be pushed towards the feed
block 104, which in turn causes a lesser amount of this substance
to find itself in the resulting output stream of combined viscous
material. Other variations can be made in the same manner to
achieve different color patterns.
[0084] In the embodiment depicted in FIG. 2, the control of the
first flow rate may be achieved by operating the variable speed
motor 604 such as to cause the extruder screw 602 to vary its speed
of rotation between an upper threshold and a lower threshold over a
time period. FIGS. 4A and 4B show charts illustrating variations of
the speed of operation of the extruder screw 602 over time in
connection with extruder 106. It is to be appreciated that the
examples shown in FIGS. 4A and 4B have been set forth for the
purpose of illustration only and that many other suitable manners
of varying over time the rate of flow of the viscous material 110
released by the primary extruder 106 may be contemplated and will
become apparent to the person skilled in the art in view of the
present description.
[0085] Optionally in some embodiments, such as the specific one
depicted in FIG. 3, the electronic control element 606 of the flow
rate controller 152 may provide one or more user operable controls
700 702 732 for allowing a user to set the lower flow rate
threshold and/or the upper flow rate threshold and/or the time
interval in order to control at least in part visual
characteristics of the color pattern in the stream of combined
viscous material exiting the system. The user operable controls 700
702 732 may include mechanically actuated switches that allow a
user to providing control commands to increase or decrease a
corresponding flow control parameter (for e.g. the lower flow rate
threshold, the upper flow rate threshold or the time period).
Optionally, display areas 704 708 734 may be provided showing
values of the flow control parameters. It is to be appreciate that,
although the electronic control element 606 shown in FIG. 3 has
been shown as including a dedicated control interface incorporating
user operable controls, in alternative embodiment such control
interface may be provided on the display screen of a general
purpose computing device in communication with the electronic
control element 606 and programmed to display a control interface
including user operable controls of the type described above.
[0086] In the context of the present invention, the extruder 106
and one or more of extruders 120.sub.1, . . . ,120.sub.N produce
plastic mixtures 110 122 of different colors and, optionally
different viscosities. In a specific, non-limiting example, the
system 100 may include a extruder 106 and one secondary extruder
120.sub.1 which producing plastic mixtures 110 122. In another
example, the system 100 may include one primary extruder 106 and
two secondary extruders 120.sub.1 120.sub.2 each of which is
producing a plastic mixture of a different color and, optionally
different viscosity.
[0087] In a practical embodiment, the plastic mixture 110 released
by the (primary) extruder 106 is characterized by a first viscosity
and the plastic mixture 122 released by the (secondary) extruder
120 has a second viscosity. The first viscosity and the second
viscosity may be essentially the same or may be distinct from one
another. The first viscosity may be lower (or higher) than the
second viscosity. In embodiments in which there may be multiple
(secondary) extruders 120, the plastic mixtures released by each
(secondary) extruder may have the same (or similar) viscosity or,
alternatively, may each have a distinct viscosity.
[0088] The use of materials having different viscosities may reduce
an amount of color blending between the first color and the second
color when the materials are combined in the feedblock 104 and
static mixer 108 as will be described later on in the present
document. The respective viscosities of the materials released by
the (primary) extruder 106 and the (secondary) extruder(s) 120 may
also be expressed in terms of high load melt index (HLMI). In this
regard, the first viscous material may be associated with a first
high load melt index (first HLMI) and the second viscous material
may be associated with a second high load melt index (second HLMI).
The first HLMI may be greater (or less) than the second HLMI.
[0089] It has been observed that using materials with differing
HLMIs reduces the amount of blending between the materials. The
greater the difference in high load melt index, the lesser the
amount of blending appears to occur. The first HLMI may be at least
about ten times (10.times.); at least about twenty times
(20.times.); or at least about one hundred times (100.times.) the
second HLMI. It is to be appreciated that, in practical
implementations, the use of material having different viscosities
may achieve different color effects compared to the use of
materials of uniform viscosities and that such materials may be use
alone or in combination with the variation in flow rate of the flow
released by the primary extruder 106.
[0090] The plastic mixture 110 released by the (primary) extruder
106 and the one or more plastic mixtures 122 released by the one or
more (secondary) extruders 120.sub.1, . . . ,120.sub.N are then
provided to the feed block 104.
[0091] The feed block 104 is configured for combining the flows 110
122 of viscous plastic output by the different extruders 106
120.sub.1, . . . ,120.sub.N into a single patterned stream of
combined viscous plastic, as will be discussed further below.
[0092] In the example depicted, the feed block 104 is comprised of
multiple sequence feed blocks 104.sub.1 . . . 104.sub.N where each
feed block injects an additional stream of viscous material
released by a respective secondary extruder 120.sub.1, . . .
,120.sub.N into the stream of viscous material released by first
(primary) extruder 106 or released by a previous feed block in the
sequence. It will however be appreciated that other configurations
for feed block 104 are possible in alternative implementations. For
example, feed block 104 may be comprised of a single modules having
N+1 input streams, where N corresponds for the number of secondary
extruders 120.sub.1, . . . ,120.sub.N in the system.
[0093] FIG. 6 illustrates a non-limiting example of a possible
configuration for the feed block 104, for the case in which the
system 100 is formed of one primary extruder 106 and two secondary
extruders 120.sub.1 and 120.sub.N, wherein the primary extruder 106
releases a flow 110 of viscous material of a greater size than the
flows 122 released by each of the secondary extruders 120.sub.1 and
120.sub.N. Thus, the feed block 104 receives three distinct flows
110 122 of viscous plastic, each of which is input to the feed
block 104 from the associated extruder 106 and 120.sub.1 and
120.sub.N via a respective feed port 270 200.
[0094] The feed block 104 also includes a programming section 202,
which receives the flows 110 and 122 from the feed ports 270 200
into corresponding channels 284 204. This programming section 202
is operative to shape and position the flows 110 and 122 according
to a predetermined pattern, whereby the flows undergo a programming
of sorts within the channels 284 204 in order to produce a desired
pattern for the stream of combined viscous material. In the example
shown in FIG. 6, the channels 284 204 of the programming section
202 are designed to produce a pattern of layers where the layer
associated with the flow 110 is shown as having a greater
volume/size that the layers associated with the flows 122 to
accommodate the higher flow rate of the first viscous material in
the present example. It is to be appreciated that different sizes,
shapes and layouts for the channels 284 204 of the programming
section 202 may also be used, in order to produce different
patterns for the stream of combined viscous material.
[0095] Note that the programming section 202 of the feed block 104
may be designed to divide a particular flow 110 or 122 into two or
more sub-flows, for producing a different pattern for the stream of
combined viscous material. In a specific example, assume the feed
block 104 receives two flows 110 and 122, one that flow 110 is
translucent in color and that flow 122 is red in color. The
programming section 202 may divide the red flow 122 into two red
sub-flows, and orient these sub-flows such that the translucent
flow 110 is sandwiched between the two red sub-flows, according to
a particular layout and pattern.
[0096] Finally, the feed block 104 includes a transition section
206, operative to fuse together the separate flows 110 and 122, for
generating the patterned stream of combined viscous material. As
seen in FIG. 6, the channels 288 208 of the transition section 206
are oriented such that their output ports 210 are located
immediately adjacent one another. As the distinct flows 110 and 122
exit the respective output ports 210, the flows of the viscous
plastics, fuse together into a single, combined stream of viscous
plastic.
[0097] In the context of the present invention, the stream of
combined viscous material generated by the feed block 104 is
characterized by zones of material having different colors and,
optionally, different viscosities. More specifically, at least one
zone of material may be formed of a first viscous plastic material
of a first color and first viscosity (material "A") and another
zone may be formed of a second viscous plastic of a second color
and second viscosity (material "D").
[0098] As mentioned above, the stream of combined viscous material
released by the feed block 104 may take on different patterns,
without departing from the scope of the present invention. Rather
than a horizontal layer pattern, the feed block 104 may combine,
the different flows 110 122 according to a vertical layer pattern,
a ring pattern, a tube pattern or a pie chart pattern, among many
other possibilities. In the case of the ring pattern, each separate
flow 110 122 of viscous plastic may be formed into a concentric
ring, where the rings of different colors and sizes are fused
together to form a tube of combined viscous plastic characterized
by adjacent zones of different colors and, optionally, different
viscosities. In the case of the tube pattern, the separate flows
110 122 may be positioned with respect to one another such that,
when fused together, they form an elongate tube, characterized by
adjacent zones of different colors and, optionally, different
viscosities.
[0099] FIGS. 9A, 9B, 9C and 9D show examples of cross-sections of
combined streams of viscous material that may be generated using
different practical embodiments of the feed block 104. For example,
FIG. 9A shows examples of cross-sections including (a) a first
viscous material ("A") only; (b) first viscous material ("A") and
second viscous material ("D"); and (c) first viscous material
("A"), second viscous material ("D") and third viscous material
("E"). It is to be understood that there is a myriad of other
possible configurations and that the examples here have been shown
for the purpose of illustration only.
[0100] Note that a generally uniform transition of the flows 110
122 from the extruders 106 120 to the feed ports 270 200 of the
feed block 104, as well as from one component to another within the
feed block 104, without any brusque variations in the channel
dimensions may assist in reducing the likelihood of stagnation of
the viscous plastic material within the feed block 104.
[0101] The use of feed blocks in extrusion processes is well known
in the art and, as such, additional details pertaining to the feed
block structure and functionality will not be described in further
detail herein.
[0102] Specific to the present invention, the stream of combined
viscous material released by the feed block 104 is fed through a
static mixer pipe 108. The static mixer 108 is operative to act on
the stream of combined viscous material for partially mixing the
adjacent zones of different colors (and optionally different
viscosities) in order to create color effects in the stream of
combined viscous material.
[0103] Static mixers are known in the industry to be useful for
effectively mixing fluids, by executing the operations of division
of flow, radial mixing and flow reversal. The most common type of
static mixer is the helical static mixer, as seen in the example of
FIG. 7, which includes a series of static elements positioned
adjacent another. Each element may be formed of a rectangular plate
twisted by 180 degrees, which splits the oncoming flow in half and
then turns it through 180 degrees. Each element in the series may
be rotated 90 degrees with respect to the preceding element, so as
to constantly subdivide the flow. When two fluids of different
colors enter a static helical mixer pipe, the dividing and
overturning motion applied to the fluids by the elements of the
mixer results in a gradual blending of the two fluids. More
specifically, as the fluids go along the curves of each element,
they are rotated radially towards the pipe wall, or rotated back to
the center. Furthermore, as the fluids pass from one element to the
next, the fluids are bisected and they change direction to the
right or to the left, the force of inertia that suddenly occurs
creating a strong flow reversal motion that results in stirring and
mixing of the fluids.
[0104] The color pattern in the stream released by the static mixer
108 is configured at least in part based on a radial orientation of
the static mixer. The color pattern in the stream may be altered by
performing a rotation of the static mixer 108 by a pre-determined
rotation amount. The pre-determined rotation amount may be
established based on an internal structure of the static mixer 108
such that upon exiting the static mixer a desired effect may be
achieved in the stream of viscous material. In specific practical
implementations, the pre-determined rotation amount may be a
rotation of about 45.degree., 90.degree., 135.degree. or
180.degree. however other rotation amount may also be suitable for
other static mixers.
[0105] Note that, for fluids of different types and/or viscosity, a
different number of elements may be required in the static mixer in
order to obtain a complete mixing of the two or more fluids from
entry into the static mixer to output from the static mixer.
[0106] Different types of static mixers exist for uniformly mixing
fluids in order to produce a homogenous mixture, such as the
example shown in FIG. 8. Such static mixers are all designed around
the same principle, notably passing the viscous fluids through a
series of elements that cause the fluids to undergo different flow
patterns resulting in the mixing of the fluids. The present
invention is not limited to any particular type or design of static
mixer.
[0107] Under the present invention, the static mixer 108 may be
characterized by a specific number of elements, such that, upon
exit from the static mixer 108, only a partial mixing of the
different colored zones of the stream of combined viscous material
has occurred, creating a blended, gradation in the colors of the
stream of combined viscous material.
[0108] More specifically, upon entering the static mixer pipe 108,
the stream of combined viscous material includes adjacent zones of
first and second colors (and optionally first and second
viscosities) respectively. The static mixer 108 is operative to mix
together a portion of the zones such that, when the stream of
combined viscous material exits the static mixer 108, the stream of
combined viscous material may be characterized by zones of a third
color, different from the first and second colors. It should be
understood that the zones of color that exit the static mixer 108
are not necessarily clearly defined zones. In a first embodiment
there can be a sharp transition between the color of one zone and
the color of an adjacent zone, thereby creating clearly defined
zones. However in an alternate embodiment, there can be a slow
color gradation from the color of one zone to the color of an
adjacent zone, such that the border between the two zones is not
clearly defined. In addition, the shapes of the zones can vary. For
example, the zones can be substantially straight, or can be wavy or
curved. Likewise, the zones can be horizontally oriented,
vertically oriented, or diagonally oriented at any angle between
horizontally oriented and vertically oriented.
[0109] Typically, when the stream of combined viscous material
exits the static mixer 108, the third zone of a third color is a
combination of the colors of the first and second zones. For
example, if the stream of combined viscous material that enters the
static mixer 108 includes a first zone that is yellow and a second
zone that is red, then typically, the stream of combined viscous
material that exits the static mixer may include a third zone that
is a shade of orange.
[0110] Alternatively, when the stream of combined viscous material
exits the static mixer 108, the third zone of the third color is
not necessarily located between the first and second zones of the
first and second color. Instead, it is possible that the third zone
of the third color is located between two zones of the first color,
or two zones of the second color. For example, if the stream of
combined viscous material that enters the static mixer 108 includes
a first zone that is white and a second zone that is blue, then the
stream of combined viscous material that exits the static mixer may
have a third zone that is a lighter shade of blue. As such, it
should be understood that for the purposes of the present
invention, the third color can be a lighter shade of one of the
first and second colors. In addition, it is possible that the
stream of combined viscous material that exits the static mixer 108
will not include a zone of white, and that instead the stream of
combined viscous material includes a zone of the light blue located
between two zones of the blue that entered the static mixer.
[0111] Note that the static mixer pipe 108 may include two or more
static mixers, for acting simultaneously on different portions of
the stream of combined viscous material as the stream passes
through the pipe 108.
[0112] Take for example the case where the system 100 includes a
first extruder 106 producing a flow 110 of translucent viscous
plastic, a second extruder 120.sub.1 producing a flow 122 of blue
viscous plastic and a third extruder 120.sub.2 producing a flow 122
of yellow viscous plastic. Assume that the feed block 104 is
operative to combine these three separate flows 110 122,
characterized by: (a) a zone of yellow; (b) a zone of blue and (c)
a translucent zone. With reference to FIG. 9A(c) and FIG. 10, as
this combined stream passes through the static mixer pipe 108, the
three zones of color are partially mixed together. Thus, other
zones, green in color, may be created around the yellow and blue
zones of the stream as well as around the translucent zones.
Additional zones of color may also be created, located between the
green zone and the yellow zone, as well as between the green zone
and the blue zone. Upon its exit from the static mixer 108, the
stream of combined viscous material of viscous plastic may include
a gradation in color from yellow to blue, and includes zone of
different colors.
[0113] Note that the length of the static mixer 108 that is
necessary to obtain a partial mixing of the different colored zones
of the stream of combined viscous material of viscous plastic may
vary for different implementations of the system 100. The present
invention is not limited to any specific length, or number of
elements, for the static mixer pipe 108.
[0114] The selection of an appropriate static mixer 108 is based on
certain predetermined parameters, including the diameter, length
and orientation of the elements themselves within the static mixer
108. Furthermore, the determination of the appropriate dimensions
for the static mixer 108 will depend on the type of plastic
material in use within the system 100, as well as the respective
rate of flow for each extruder 106 120.sub.1, . . . , 120.sub.N and
the total rate of flow for the stream of combined viscous material
output by the feed block 104
[0115] In a specific, non-limiting example, in order to create a
sheet of plastic having a red-orange-yellow wave-like appearance
once it has exited the static mixer 108, a first extruder having a
3.sup.1/2 inch diameter is supplied with new plastic granules and
4% red colorant, and a second extruder having a 1.sup.1/2 inch
diameter at 75 rpm is supplied with new plastic granules and 4%
yellow colorant. In this non-limiting example, the first extruder
is operated at a variable speed that fluctuates between about 15
rpm and 50 rpm over a 40 second time interval. From the extruders,
viscous flows of red and yellow plastic are fed into a feedblock
that forms the flows of red and yellow plastic into a stream of
adjacent zones, which it feeds into a helical static mixer having a
21/2 inch diameter made of 3 elements.
[0116] In another specific, non-limiting example, in order to
create a sheet of plastic having a blue, white and light blue
appearance once it has exited the static mixer, a first extruder
having a 3.sup.1/2 inch diameter is supplied with new plastic
granules and 2% white colorant, and a second extruder having a
1.sup.1/2 inch diameter at 70 rpm is supplied with new plastic
granules and 4% blue colorant. In this other non-limiting example,
the first extruder is operated at a variable speed that fluctuates
between about 12 rpm and 60 rpm over a 20 second time interval.
From the extruders, the flows of white and blue viscous plastic are
fed into a feedblock that forms the two flows into a three layer
stream of blue, white and blue which it feeds into a helical static
mixer having a 2.sup.1/2 inch diameter made of 6 elements.
[0117] Note that different orientations of the static mixer 108
with respect to the longitudinal plane of the stream of combined
viscous material will result in different patterns of color
gradation in the stream of combined viscous material at the output
of the static mixer pipe 108. For example, in the case of a helical
static mixer 108, if the last element of the static mixer 108 is
oriented horizontally with respect to the plane of the stream of
combined viscous material, the static mixer 108 will tend to
produce longitudinal bands of color in the stream of combined
viscous material. In contrast, if the last element is oriented
vertically with respect to the plane of the stream of combined
viscous material, the static mixer 108 will tend to produce
vertical bands of color in the stream of combined viscous
material.
[0118] Furthermore, different orientations of the static mixer 108,
as well as different rates of flow for the different extruders 106
120.sub.1, . . . , 120.sub.N, may produce colored zones of
different sizes within the stream of combined viscous material.
Thus, the final color pattern achieved in the stream of combined
viscous material by the static mixer 108, including both size and
color dominance, is dependent on the respective rate of flow of the
extruders 106 120.sub.1, . . . , 120.sub.N, as well as on the
orientation of the static mixer 108.
[0119] The die 102 receives the stream of combined viscous material
from the static mixer pipe 108, and is operative to shape the
stream of combined viscous material into its final product form,
such as a sheet or a tube, among many other possibilities. In the
non-limiting example shown in FIG. 1, the die 102 is operative to
produce sheets of plastic 112 from the stream of combined viscous
material. Different shapes and sizes of dies may be used within the
system 100 to generate different forms and types of plastic
products. The structure and functionality of such dies are well
known to those skilled in the art, and as such will not be
described in further detail herein.
[0120] FIGS. 11A and 11B illustrate two examples of products that
may be formed by the die 102. In FIG. 11A is shown an example of a
sheet of plastic resulting from a three-color (translucent, yellow
and blue) extrusion process. In its final product form, the sheet
of plastic is characterized by wave-like color gradation effects
including translucent zones (the color "A" from the first extruder
106), as well as waves of blue (the color "D" from extruder
120.sub.1), of yellow (the color "E" from extruder 120.sub.N) and
waves of green (resulting from a partial blending of color "D" and
color "E").
[0121] In FIG. 11B is shown an example of a tube of plastic
resulting from the same three-color extrusion process.
[0122] The product resulting from the extrusion process described
in the present document, such as the sheet or tube of plastic, may
be used as is, in different applications. For example, the sheets
of plastic may be cut out to form tobogganing carpets, also
referred to as crazy carpets. Alternatively, the product resulting
from the extrusion process may be thermoformed into different
shapes or final products. For example, the sheets of plastic
characterized by the wave-like color gradation effects may be
thermoformed into pedal boats, kayaks, canoes, stand-up paddle
boards or other similar watercraft products. They may also be
thermoformed into recreational products, such as toboggans and
pools, among many other possibilities. Whether thermoformed or not,
a main advantage of the extruded product resulting from the
above-described extrusion process is to provide an esthetically
appealing appearance to the consumer or user.
[0123] FIG. 14A shows kayaks manufactured using one or more plastic
sheets of extrudable material with wave-like color gradation
effects created using a process embodying aspects of the invention
described in the present document.
[0124] More specifically, kayaks of the type depicted in FIG. 14A
may be manufactured by molding two or more of the manufactured
sheets of extrudable material using thermoforming to shape the two
of more manufactured sheets into a kayak shape. In such process,
one or more of the two or more of the manufactured sheets may have
color effects created using a process embodying aspects of the
invention described in the present document.
[0125] FIGS. 14B and 14C show top plan and side views respectively
of a stand-up paddle board (SUP) manufactured using plastic sheets
of extrudable material created using a process embodying aspects of
the invention described in the present document.
[0126] FIG. 12 is a flowchart illustrating a process that may be
implemented by the system 100 for creating color gradation effects
in extruded plastic material.
[0127] As shown, at step 1200, a flow of a first viscous material
of a first color is provided through the primary extruder 106
(shown in FIG. 1). The first viscous material (material "A") is
released by the primary extruder 106 at a first rate of flow. In a
first specific implementation, when providing the first viscous
material (material "A"), the first rate of flow may be caused to
vary over time. Varying the rate of flow of the first viscous
material over time may allow modulating over time an amount of the
first viscous material (material "A"), relative to an amount of the
second viscous material (material "D") that finds itself in the
stream of combined viscous material at different moments in time,
which may allow the color effects created to vary over time and
create wave-like patterns.
[0128] FIG. 5A shows color effects that may be produced in
extrudable plastic material using the system 100 in which the flow
rate controller 152 maintains a generated constant first flow rate
in connection with extruder 106 (in other words no flow rate
variation is applied to extruder 106). FIG. 5B shows color effects
that may be produced in extrudable plastic material using the
system 100 in which the flow rate controller 152 varies the flow
rate of the extrudable material 1101. As can be observed, the
modulation of the flow rate may allow creating wave-like color
gradation effects in the resulting plastic material.
[0129] In one of the non-limiting practical embodiments
contemplated, the first viscous material "A" is a base or carrier
color. For example, the first viscous material "A" may be a
translucent material and/or a neutral color such as a white (or off
white), grey or any other suitable base of color.
[0130] At step 1202, which is performed concurrently with step
1200, a flow of a second viscous material of a second color,
different from the first color, is provided through one of
secondary extruders 120 (shown in FIG. 1) The second viscous
material (material "D") is released by the secondary extruder 120
at a second rate of flow. In a first specific implementation, when
providing the second viscous material (material "D"), the second
rate of flow is kept substantially constant over time. It is
however to be understand that this need not be the case in all
implementations and that the second flow rate may also be caused to
vary over time in a manner similar to that described above with
reference to the flow of the first viscous material.
[0131] In some specific practical implementations, the second rate
of flow associated with the second viscous material of the second
color may be lower than the first rate of flow. In such
implementations, the first viscous material ("A") constitutes a
larger portion of the resulting stream of combined viscous material
than the second viscous material ("D"). In specific practical
implementations, the second rate of flow may be no more than 50% of
the first rate of flow, preferably no more than 30% of the first
rate of flow and more preferably no more than 20% of the first rate
of flow.
[0132] In one of the non-limiting practical embodiments
contemplated, the second viscous material "D" is an accent color
intended to be carried by the base (or carrier color) of material
"A". For example, the second viscous material "D" may be a bright
colored material and such as a red, blue, pink, green, yellow or
any other color that may add visual interest to the base (or
carrier color) of material "A".
[0133] In some implementations, the second viscous material "D"
provided at step 1202 may have a viscosity that is distinct from
the viscosity of the first viscous material "A" to reduce an amount
of color blending between the first color and the second color in
the stream of combined viscous material.
[0134] At step 1204, the first and second flows are combined
together in the feed block 104 (shown in FIG. 1) in a predetermined
pattern to form a stream of combined viscous plastic.
[0135] Next, at step 1206, the stream of combined viscous plastic
generated at step 1204 is fed through the static mixer 108 (shown
in FIG. 1), which is configured to partially mix the first viscous
material ("A") and the second viscous material ("D") such that upon
exiting the static mixer, the first material of the first color and
the second material of the second color form a color pattern in the
stream of combined viscous material. In some cases, the color
pattern created includes zones of the first color, zones of the
second color and (optionally) zones of a third color, different
from the first and second colors. The third color is typically a
blend between the first color and the second color.
[0136] In cases where, the second viscous material "D" provided at
step 1202 has a viscosity that is distinct from the viscosity of
the first viscous material "A", colors may tend to remain more true
to the original first and second colors, and exhibit less color
blending, than in cases where the viscosities of the first and
second viscous materials are substantially the same.
[0137] Note that the above process may be applicable to various
different suitable types of extrudable material, and is not limited
to plastic applications.
[0138] FIG. 13 depicts a system 800 for manufacturing plastic
sheets, according to an alternative example of implementation of
the present invention. As shown, system 800 is used for
manufacturing plastic products, such as plastic sheets, with color
effects being provided in one or more surface layers of the
product. In this case, extruder 806.sub.1, which includes extruder
816 connected to flowrate controller 852 as well as extruders
860.sub.1, . . . ,860.sub.N, in combination with the feed block 804
(which in this example is comprises of feed block sequence
804.sub.1 . . . 804.sub.N) and the static mixer 808, produces a
stream of combined viscous plastic 810.sub.1 characterized by color
effects, in a similar manner as described above with regard to the
system 100 (shown in FIG. 1).
[0139] This stream 810.sub.1 is then fed into a combining device
where it is combined with the separate flows 800 of viscous plastic
output by the extruders 806.sub.2, . . . ,806.sub.N. In the
specific example shown in FIG. 13, the combining device includes
the feed block 812. The feed block 812 produces a co-extruded
stream of viscous plastic 810.sub.2, having at least one layer,
typically a surface layer, characterized by color effects. The die
814 then receives this co-extruded stream 810.sub.2, and is
operative to mold the plastic stream into its final form, for
example a sheet or a tube.
[0140] Note that the feed blocks 804 and 812 may be similar in
structure and functionality to that described above with regard to
the feed block 104.
[0141] In an alternative embodiment wherein the die 814 is
configured to combine the streams from the static mixer pipe 808
and the extruders 806.sub.2 806.sub.N into a co-extruded sheet
prior to forming the sheet into its final form, the feedblock 812
can be omitted, and the combining device may simply include the die
814.
[0142] Thus, in this variant example of implementation, plastic
products are formed in which the color effects may be limited to an
outer surface of the product. Note that, in this case, one or more
of the extruders 806.sub.2, . . . 806.sub.N may be fed with
recycled plastic granules, if the respective one or more layers of
plastic generated by these extruders are not visible on the
finished product. Alternatively, each of the extruders 806.sub.2, .
. . 806.sub.N may be producing a plastic mixture of a predetermined
and specific color, depending on the specific applications and end
products being formed.
[0143] Note that any one of the extruders 806.sub.2, . . .
806.sub.N may be set up in the same way as extruder 806.sub.1, such
that two or more layers of the final plastic product are
characterized by color effects. These color effects may differ from
one layer to another, since the extruder flow rates and static
mixer orientations may vary from one extruder arrangement to the
other.
[0144] Alternatively, the die 814 may be provided with multiple
feed ports, such that the die 814 itself could directly receive the
stream of viscous plastic 810.sub.1 from the extruder 806.sub.1, as
well as the flows 800 from the extruders 806.sub.2, . . .
806.sub.N. Thus, the die 814 would act to combine the stream 810,
and the flows 800 into the co-extruded stream of viscous plastic
810.sub.2, after which the die 814 would shape the stream 810.sub.2
into the final product form. Note that, in this case, the die 814
takes on the responsibility of the feed block 812, which is no
longer required within the system 800.
[0145] Although various embodiments have been illustrated, this was
for the purpose of describing, but not limiting, the invention.
Various modifications will become apparent to those skilled in the
art and are within the scope of this invention, which is defined
more particularly by the attached claims.
[0146] The foregoing is considered as illustrative only of the
principles of the invention. Since numerous modifications and
changes will become readily apparent to those skilled in the art in
light of the present description, it is not desired to limit the
invention to the exact examples and embodiments shown and
described, and accordingly, suitable modifications and equivalents
may be resorted to. It will be understood by those of skill in the
art that throughout the present specification, the term "a" used
before a term encompasses embodiments containing one or more to
what the term refers. It will also be understood by those of skill
in the art that throughout the present specification, the term
"comprising", which is synonymous with "including," "containing,"
or "characterized by," is inclusive or open-ended and does not
exclude additional, un-recited elements or method steps.
[0147] Unless otherwise defined, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention pertains. In the
case of conflict, the present document, including definitions will
control.
[0148] Although the present invention has been described in
considerable detail with reference to certain embodiments thereof,
variations and refinements are possible and will become apparent to
the person skilled in the art in view of the present description.
The invention is defined more particularly by the attached
claims.
* * * * *